The level structure of 151Pm

Abstract

Levels in 151Pm have been populated using the 150Nd( 3He, d) 151Pm, 150Nd(α, t) 151Pm and 152Sm(t, α) 151 Pm reactions. In each case the outgoing charged particles were analyzed with a magnetic spectrograph and detected with photographic emulsions. Relative spectroscopic factors were obtained by comparing the experimental cross sections with those predicted by DWBA calculations. The results were interpreted in terms of the Nilsson model with Coriolis mixing effects included. The present work confirms the 5 2 + [413] assignment for the ground state band and the 3 2 + [411] assignment for the band based on the 255.7 keV level. However, the 11 2 − state at 345 keV, previously assigned as the particle state 11 2 5 2 − [532] , was found to have a large spectroscopic factor in the pick-up as well as the stripping reactions so this level must have significant admixtures of hole states. Coriolis coupling calculations, carried out with typical parameters, can explain these results by bringing in components of the 3 2 − [541] and 1 2 − [550] hole states, which also originate from the h 11 2 shell. Two other 11 2 − states, at ≈ 640 keV and 782 keV, have also been attributed to strongly mixed configurations although the latter is predominantly the 11 2 7 2 − [523] state. Several positive-parity orbitals with low K-values appear to have their strengths distributed over many states, possibly due to mixing with each other and with nearby vibrational states.